Installation manual about PHP 7.3 - but requirement is PHP 7.2

[Tantuss]

Explanation of needed software: https://docs.akeneo.com/master/install_pim/manual/system_requirements/system_install_ubuntu_1804.html

With PHP 7.3.12 installed, I get 'composer install' with this error:

Updating dependencies (including require-dev) Your requirements could not be resolved to an installable set of packages.

Problem 1 - akeneo/pim-community-dev v3.2.26 requires php 7.2.* -> your PHP version (7.3.12) does not satisfy that requirement. - akeneo/pim-community-dev v3.2.25 requires php 7.2.* -> your PHP version (7.3.12) does not satisfy that requirement. - akeneo/pim-community-dev v3.2.24 requires php 7.2.* -> your PHP version (7.3.12) does not satisfy that requirement. - akeneo/pim-community-dev v3.2.23 requires php 7.2.* -> your PHP version (7.3.12) does not satisfy that requirement. - akeneo/pim-community-dev v3.2.22 requires php 7.2.* -> your PHP version (7.3.12) does not satisfy that requirement. - akeneo/pim-community-dev v3.2.21 requires php 7.2.* -> your PHP version (7.3.12) does not satisfy that requirement.